An adhesive composition containing a 2-cyanoacrylic acid ester quickly establishes a strong bonding among various types of materials attributed to the unique anion polymerization characteristics exhibited by its principal component, 2-cyanoacrylic acid ester, which initiates polymerization under the presence of weak anion provided by slight moisture or the like attached to a surface of an adherend. Accordingly, it is used as the so-called instantaneous adhesive in a wide range of fields including industrial, medical, and household applications. Because the cured product of this adhesive composition is hard and brittle, it exhibits excellent adhesion strength against shear; however, it is problematic in that peel adhesion strength and impact adhesion strength are low, and particularly cold/hot cycle resistance of the adhesion strength is inferior. To overcome these problems, modification methods have been proposed heretofore, which include adding various types of elastomers and additives (see, for instance, Patent Documents 1 and 2). Also proposed are methods of blending therein a slightly soluble rubber or elastomer particles (e.g., Patent Documents 3 and 4). On the other hand, also known in the art are methods of improving the function of the adhesive by blending a bifunctional 2-cyano-3-vinylacrylic acid ester in the adhesive composition (e.g., Patent Document 5), or blending a phase transfer catalyst having a specific structure in the adhesive composition (e.g., Patent Document 6).